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  1. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    NFPA is probably not very detailed for PE commissioning pressure tests. There are standards for PE installation. We as a fire company pressure test sprinkler pipework all the time, but we leave underground stuff, especially PE visco-elastic pipe to the civil contractor as the pressure testing...
  2. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    The pipe is PN16 as stated on the plans. The pressure decay over time for the commissioning test was due to creep. The recent test we did does follow a similar curve, 1 bar drop in 1 hour then 1 bar drop after another 7 hours. No pressure relief. I will find some literature on PE pipe to see how...
  3. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    I didn't see your response -thirtynine. The sprinklers are for fire. I tend to think it is a leak but was interested in the viscoelastic and temperature effects of the PE pipe. The installing plumber talked about needing to backfill the black PE before pressure testing - otherwise the sun...
  4. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    It is about 80 m of 125OD HDPE PN16 pipe. Probably there is another 5x65mm tee-offs to 5 classrooms at the school before it turns back to steel above ground but yet to confirm- totaling <20m length.
  5. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    It will be PN16 pipe, not sure on grade and SDR but it will be standard. The ground temperature I am not sure - 5-10 deg C. The above ground ambient is typically 15-20 deg C.
  6. hgordon

    Viscoelastic Behaviour of PE Pipe - In a Sprinkler System

    Hi all, I am hoping someone has experience with underground polyethylene pipe. We have a sprinkler system which is dropping pressure consistently, probably from a leak, but I thought maybe the PE pipe could be creeping causing the pressure to drop. The sprinkler pipework consists of U/G PE pipe...
  7. hgordon

    Fire Pump with Long Exhaust Run

    Thanks for feedback, we are looking at the vertical and another horizontal run option. I specified sch10 stainless or sch40 carbon steel. Stainless thinwalled tube may also be Ok? Have noted to insulate the pipe in the pump room but not when it exits. The specs will he confirmed by the...
  8. hgordon

    Fire Pump with Long Exhaust Run

    Carbon steel exhuast pipe is just black steel pipe with no corrosion coating or other inhibitors? Thanks,
  9. hgordon

    Fire Pump with Long Exhaust Run

    thanks, it makes good sense to hang it from the top with guides.
  10. hgordon

    Fire Pump with Long Exhaust Run

    Hi all, We are working on a hotel job and need to install 2x diesel driven pumps for sprinkler and hydrant. The pump room is becoming enclosed by the new hotel extension, which makes things difficult for the exhaust route for the diesel engines. There is one micky mouse way to get it outside...
  11. hgordon

    Anchor Rod Gap Between Bracket and Concrete

    Hi there, Please see the attached PDF. We supply containerised (20 foot) fire pumpsets and usually install the seismic hold down brackets flush to the concrete base. However in this particular installation the container is 40mm off the concrete and we prefer not to make it flush as pipe and...
  12. hgordon

    Thrust Blocks Required ?

    I think fire pump discharge pipe movement/shaking/vibration is not so much thrust forces (except for pump initial startup to pressurize the pipework) but more to do with the turbulence the elbows see during flow conditions - with higher velocities creating more shaking. Because the grooved...
  13. hgordon

    Thrust Blocks Required ?

    Awesome, What about a fire pipe system downstream of a pump. We try to manage thrust forces (above ground) with wall/floor braces on pipe elbows and other direction changes. The worst of the thurst force comes from the hydrostatic pressure acting at the bends - acting to push the bend fitting...
  14. hgordon

    Thrust Blocks Required ?

    Hi there, I am looking to install a 150 PE main underground with heat-fused welded joins , the PE elbows up at both ends and termiantes near ground level. Then a flanged connection will join steel pipe from a pump at one end to a valve room at the other end. I am wondering if I need to...
  15. hgordon

    Centrifugal Pumps and their Curves (Fire Pumps)

    Thanks for reply, What is a flat pressure fire system? I thought a jockey pump will help to create a flat pressure fire system? The valve is here: https://www.cla-val.com/50-49-pump-startbrpressure-relief-valve-p-149.html It stays normally open unlike a typical relief valve, to let the initial...
  16. hgordon

    Centrifugal Pumps and their Curves (Fire Pumps)

    Hi there, I am getting my head around fire pumps which start at a constant speed direct on line. When a pump starts on an empty system there is no back pressure then the pressure builds from friction or lift. So to me it starts at max flow then the flow reduces as the pressure builds until say...
  17. hgordon

    Lead Acid Battery Testing Theory

    Hi all, I am in the fire protection business where we use lead acid batteries on constant float charge to start diesel pumps for sprinklers. Our H&S department is not keen on specific gravity testing. I am more inclined to say load testing is more beneficial. Keeping in mind our sites are in...
  18. hgordon

    Exploding Lead-Acid Battery

    I believe in both cases the inter-cell welds are loose and have created the spark. Possibly the weld is bad or the vibration of the diesel next to the batteries has fractured the weld due to fatigue.
  19. hgordon

    Exploding Lead-Acid Battery

    Yeah it is strange as my boss has not had this occur in his career which is like 15 yrs. Now there has been two over 3 weeks.. The 1st battery was 4 yrs and the 2nd 4.5 yrs old. Different brands, 1st is Super Charge and 2nd is Century. We are meant to replace them every 4 years as per the...
  20. hgordon

    Exploding Lead-Acid Battery

    So looks like buckling is caused by overcharge or overdischarge, or using it in a low charge state, as well as non-uniform distribution of current over the plates. Low electrolyte probably creates some buckling as well. So believe it or not another battery as exploded at another site. This is a...

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